Arming system



E. K. CLARK ARMING SYSTEM June 8, 1954 2 Sheets-Sheet l Filed June 4, 1945 vow w www WITNESSES: afm Q MMM ATTORN EY June 8, 1954 E. K. CLARK ARMING SYSTEM Filed June 4, 1945 2 Sheets-Sheet 2 36 fsf 4/I 23 Hg. 2

37 36 JZ 4' sa WITNESSES:

lNvENTR ATTORNEY Patented June 8, 1954 UNITED STATES ARMING SYSTEM Navy Application June 4, 1945, Serial No. 597,57 6

(Cl. IGZ-70.2)

I Claims.

This invention relates generally to ordnance fuses and more particularly to an improved type of arming mechanism for use in such fuses.

In certain of its aspects this invention is related to a copending application of the applicants Serial No. 597,575 filed on the same date as this application and entitled Mechanical Device, now Patent No. 2,484,206.

Ordnance fuses sometimes include a fluid operated device such as a propeller or turbine for driving various fuse elements such as generators for supplying electrical power to the circuits of electrically controlled fuses, arming mechanisms, contact devices for establishing energizing circuits, etc. In devices of this type it is essential that provision be had for preventing operation of the iluid operated device prior to the time the fuse is intended to be used. Otherwise detonation of the projectile to which the fuse is attached may result.

One object of this invention is to provide an ordnance fuse which is entirely reliable in operation.

Another object of this invention is to provide an ordnance fuse including a fluid operated device n for supplying mechanical power to the fuse system in which the fluid operated device is mechanically restrained until the fuse is put into use.

Yet another object of this invention is to provide an ordnance fuse of the character described in which the fluid operated device is restrained from operation until the fuse is subjected to certain operating conditions.

A further object of this invention is to provide an ordnance fuse of the character described in which arming of the fuse is prevented until the fuse is subjected to certain operating conditions and said operating conditions prevail for a predetermined length of time.

A specic object of this invention is to provide a simple and effective arming mechanism for an ordnance fuse.

Other objects and advantages will become apparent upon a study of the following specification when considered in conjunction with the accompanying drawings, in which:

Figure 1 is a longitudinal cross section of an ordnance fuse embodying the principles of this invention,

Figure 2 is an enlarged detail of the arming mechanism of the fuse.

Fig. 3 is a sectional view taken on the line III- III of Fig. 2.

The proximity fuse illustrated in Fig. 1 of the drawings includes generally, a photoelectric head i comprising light sensitive devices and other electronic devices controlled thereby, a generator 2 for supplying electrical energy to the electronic system, a turbine 3 or driving the generator and operating other arming features of the fuse, some of which are not shown in the interest oi simplicity, an arming mechanism d responsive to forces imposed thereon due to accelerating movements oi the projectile to which the fuse is attached and having a time delayed operating characteristic depending upon the speed of operation of the turbine 3, and a gear reduction unit 5 operated by the turbine 3, the output oi' which, among other things, is utilized to drive contacting devices which complete certain circuits in the electrical system, for example, circuits to a heater buried in a small charge of powder, the assembly being known as a squib, to render the system operative. The fuse is detonated in proximity to the target by the response of the electronic system which effects energization of said heater, in turn igniting said powder charge in the squib forming part of a powder train for detonating the projectile. The squib and associated powder train are not shown.

Specifically the fuse structure comprises a concentric arrangement of cylindrical members and 1 within the front extremity of a projectile 8. The cylindrical members 6 and 'l are secured in concentric relation by means of a plurality of circumferentially distributed screws, one of which appears at 9. These screws pass through longitudinally disposed webs iii of the cylindrical member 'l and radially disposed spiral webs 6m integral with member t and thread into the bushing inserts l I in the generator field supporting structure l2 secured within the cylindrical member 6 by means of screws i3 threading into other threaded inserts H in the generator i-leld structure. The wall of the cylinder 'i terminates at the rear of the turbine rotor 3 while the longitudinal webs is extend further to the rear where they are secured in recesses provided in the barrier lll. This assembly is secured by means o a ring l5 through which pass a plurality of screws It alternately threadedly engaging the webs lil and the barrier lli. A threaded ring Il secured to the webs lil of cylindrical member 'l threads into the forward extremity of the projectile 8 and concentrically positions the concentric assembly of members 6 and l within the projectile body 8.

In its assembled position the fuse unit fits Within a deep cylindrical cup 8c of thin gauge metal which is clamped to the projectile body 3 at its flanged extremity by means of the clamping ring 8b. This forms a smooth surface over which the fuse unit slides when inserted into the projectile and provides a thin weatherproof seal for the high explosive charge of the projectile which is packed in the cavity 8c formed there-- about. This cup is destroyed when the fuse powder train is touched off. As a consequence the fuse powder train blasts into the high explosive.

The generator supporting structure l2 secured within the cylindrical member 6 as before described carries a shaft I9 having a cone bearing surface 23 formed thereon. The turbine rotor has the hub 2| thereof journaled on bearings which ride on the conical shaft section and the conical surface of an adjustable cone bearing 22 which threads onto the shaft I3. Permanent magnet inserts or bars, one being shown in cross section at 23, there being three which are l equally distributed around the turbine rotor 3, produce magnetic elds which link three equally circumferentially distributed coils, one of which appears in section at 2li. The coils are carried on laminated U-shaped members 25a, the extremities of which confront the inserts 23. The mag netic arrangement is such that the magnetic fields link the coils in opposite directions upon rotation of the turbine rotor 3 and thus generate an alternating voltage in the coils.

This assembly of the turbine and the generator, positions the turbine rotor 3 at the rear of the cylindrical member 6 and the cylindrical meniber l and forms a shroud around the turbine blades 25. Upon movement of the projectile through the atmosphere, air is taken into the fuse through the spiral passages 26 defined between the cylindrical members 3 and l and the spiral webs 3a. The volume transfer of this air through the intake passages 26 is due to the laminar impact of the air across the bell-shaped opening. This air stream has a velocity comn ponent due to the spiral passages in the direction of turbine rotation and impinges on the turbine blades 25. The air stream then reverses its flow through the passage 2 formed between the cylindrical member 7 and the cylindrical wall of the cup 8a, moving towards the front of the projectile where it again reverses direction and discharges into the atmosphere through the exhaust opening 28 formed at the rear of the Venturi tip 23 which is an integral part of the member '1. This air ows as a result of the large pressure diierential existing between the inlet and exhaust openings upon movement of the projectile through the atmosphere.

Rotation of the turbine rotor 3 under other than operating conditions is prevented by means of a group of pins 3! which are positioned for siiding movement in radial slots 32 the plate 33. This plate forms part of the arming mechanism 4 and frictionally engages a plate 35 carried by the plungers 36 which operate in suitable bores in the barrier il. The assembly of plate and plungers 33 forms an inertia member responsive to accelerating forces incident to propulsion of the projectile through the atmosphere as will be evident from the description of the operation hereof which is hereinafter given. Compression springs 3'! acting on the plungers, bias the plate 35 into tight frictional engagement with the plate 33. Discs 38 Which may form an integral part of the pins 3| have a peripheral conguration adapted to t the buttress type of threads turned on a member 39 secured to the iii) i nally thereof when the pins 3|, assembled on piate 33 move into engagement therewith, as hereinafter explained. Rotational movements of the turbine rotor 3 are transmitted to the gear reduction unit 5 by means of an extension 44 of the turbine rotor hub 2| extending through the threaded member 39 of the arming mechanism 4 and which terminates in a jaw type of clutch. Complementary portions of the first gear of the gear reduction unit, shown only fragmentarily at 45, intert with the projections at the extremity of the turbine rotor hub extension 44, thus providing a positive drive between the turine rotor 3 and the gear unit 5, the output of the gear unit among other things being utilized to operate certain contacting devices (not shown) to establish energizing connections for the electrical circuits of the fuse.

A better understanding of the invention may be had by consideration of a fuse installation according to this invention on a certain type of rocket propelled projectile. Such a projectile may accelerate once in free flight at the rate of 1100 feet/sec./sec. Thus the assembly of the spring biased plate 35 and plungers 33 carrying the plate and forming the inertia member must have a mass suicient to compress the springs 31 at this rate of acceleration, to move the plate completely clear of the plate or disc 33, therefreeing the plate 33 of all frictional restraint. Thus the turbine rotor 3 under the inuence of the high velocity air stream owing through the passages 26 and 2T rotates up to speed and drives the plate 33 and pin assembly 3| around in rotation. The discs 38 of the pins 3| follow the lead of the threads on the member 39 and if the accelerating forces are within predetermined limits of the mentioned 1100 ft./'sec./sec. acceleration, the pin and plate assembly remains free of frictional restraint and is driven along the threaded member 33 until the projections 42 of pins 3| pass within the boundaries of the cup 4| at which time the pin and plate assembly rotates free of the turbine rotor 3 under its inertia. Once the projections a2 are within the cup, radial movement of pins 3| is prevented. As a consequence, the spring biased plate 35, if it should now engage the plate 33 because of a drop in accelerating forces, may not push the pin and plate assembly back to the starting position, since, the discs 38 are locked in the threads and may not be ratcheted over the threads. If for any reason, the accelerating forces should drop below a predetermined value during the time interval required for the disc 33 and pin assembly to travel the distance required along the threaded member 39 before locking takes place, the springs 3'! bias the plate 35 against 'the plate 33 causing the discs to be ratcheted over the buttress type of threads on the member 39 thereby driving the pin and disc assembly back to its starting position. This locks the rotor and prevents arming of the fuse. The biasing force of the tension member 40 on the pins 3| is such as to prevent disengagement of the discs 38 from the threads as a result of centrifugal reaction, yet not of such a high value i i l as to prevent ratcheting of the discs over the threads under the forces applied by the plate 35.

It is not to be construed that application of this arming mechanism is limited to a high accelerating force such as mentioned in this discussion. It Will be apparent to one skilled in the art that the simple expedient of changing the mass of the plate and/or spring constants will provide a wide response to accelerating forces.

It is apparent that the various objects of this invention are accomplished in the device disclosed with the arming mechanism per se forming a very important integrating mechanism intermediate the turbine and gear reduction unit. This fuse assembly provides complete safety by means of a mechanism which responds jointly to the various factors described.

The foregoing disclosure and the showings made in the drawing are merely illustrative of the principles of this invention and are not to be interpreted in a limiting sense. The only limitations are to be determined from the scope of the appended claims.

claim as my invention:

l. An ordnance fuse adapted for attachment to a projectile comprising, in combination, a rotatable fluid operated member, means for supplying a uid medium under pressure for operating said fluid operated member, means responsive to said fluid operated member including a second rotatable member engaging said rotatable fiuid operated member for rotation therewith, means responsive to rotative movement of said second rotatable member for disengaging said members and adapted for disengagement with said rotatable fluid operated member upon a predetermined number of revolutions thereof, an inertia member, guide means supporting said inertia member for movement in each of two directions engaging and disengaging said second rotatable member, said guide means preventing rotation of said inertia member with respect to said fuse, spring means biasing said inertia member into engagement with said second rotatable member to prevent rotation thereof, said inertia member being responsive to predetermined acceleration of said fuse and moving from engagement with said second rotatable member, and means responsive to the rotational movements of said iiuid operated member for controlling said ing a fluid medium under pressure for rotating said fluid operated device, a rotatable member disposed for releasable engagement with said fluid operated device, a threaded member, means engaging said rotatable member with said threaded member, said threaded member being threaded in a direction to lead said rotatable member away from said fluid operated device to effect disengagement therebetween upon a suitable number of rotations of said uid operated device, an inertia member disposed for frictional engagement with said rotatable member, means restraining said inertia member from rotation with respect to said rotatable member, means resiliently biasing said inertia member into friction engagement with said rotatable member, and means responsive to rotative movements of said fluid operated device for controlling the operation of said fuse.

3. An ordnance fuse adapted for attachment to a projectile comprising, in combination, a rotatable uid operated device, means for supplying a uid medium under pressure for operating said device, a rotatable member, a threaded member, means releasably engaging said rotatable member with said rotatable uid operated device and said threaded member, an inertia member disposed for frictional engagement with said rotatable member, means resiliently biasing said inertia member into frictional engagement with said rotatable member, means restraining said inertia member from rotational movements with respect to said rotatable member, and means responsive to rotational movements of said fluid operated device for controlling the operation of said fuse.

4. An acceleration responsive mechanical device comprising, in combination, a rotatable driving member, a rotatable driven member, a threaded member, a plurality of elements carried by said driven member for releasably engaging said driven member with said driving member and said threaded member, said elements being mounted on said driven member for displacement along an axis radially of said driven member away from said threaded member, means resiliently biasing said elements to engage the threads of said threaded member, the lead of the threads of said threaded member being in a direction to effect movement of said driven member away from said driving member to cause disengagement of said elements with said driving member, upon a predetermined number of revolutions of said driving member; an inertia member, means resiliently biasing said inertia member in a direction to engage said driven member and prevent rotation thereof, said inertia member moving from engagement with said driven member in response to predetermined acceleration of said device, and means restraining said inertia member from rotational movement with respect to said device.

5. An acceleration responsive mechanical device comprising, in combination, a rotatable driving member, a rotatable driven member, a threaded member, a plurality of elements carried by said driven member for releasably engaging said driven member with said driving member and said threaded member, said elements being each mounted on said driven member for displacement along an axis radially of said driven member away from said threaded member, means resiliently biasing said elements to engage the threads of said threaded member, the lead of the threads of said threaded member being in a direction to effect movement of said driven member away from said driving member to cause disengagement of said elements with said driving member upon a predetermined number of revolutions of said driving member, an inertia member disposed to engage said driven member to prevent rotation thereof, means resiliently bias,- ing said inertia member in a direction to engage said `driven member, said inertia member disengaging said driven member upon predetermined; acceleration of said device, means restraining said inertia member from rotational movement with respect to said device, and means for restraining said elements from displacement movements upon disengagement of said elements with said driving member.

6. An acceleration responsive mechanical de.- vice comprising, in combination, a rotatable driving member, a rotatable driven member, means for releasably engaging said driving member and said driven member, operable after a predetermined number of revolutions of said members to effect disengagement thereof, an inertia member normally engaging said driven member to prevent rotation thereof and responsive predetermined acceleration of said device to disengage said driven member and permit rotation thereof, and means for locking said driven member upon movement thereof to a position in which it is disengaged from said driving member.

7. An acceleration responsive mechanical device comprising, in combination, a rotatable driving member rotatable in one direction, a rotatable driven member, a threaded member disposed coaxially of said driving member, means threadedly engaging said driven member With said threaded member and supporting said driven member in a position adjacent to and coaxially disposed of said driving member, clutch means mechanically engaging said driving and driven members, said clutch means disengaging said driving and driven members upon predetermined movement of said driven member away from said driving member, motion of said driven member away from said driving member being effected upon rotation of said driven member by said driving member, the helix of said threaded member being in a direction to move said driven member axially away from said driving member upon rotation of said driven member in said one direc- Eil tion, an axially movable inertia member axially disposed of said driven member, means resiliently biasing said inertia member axially into engagement with said driven member, said inertia member moving from engagement With said driven member in response to predetermined acceleration of said device, and means restraining said inertia member from rotation With respect to said device to prevent rotation of said driven member when said inertia member is in a position engaging said driven member.

Cited in the file of this patent UNITED STATES PATENTS Number Name Date 565,524 Thompson Aug. 11, 1896 880,818 Pangher Mar. 3, 1908 1,233,224 Hale July 10, 1917 1,234,358 McCandlish July 24, 1917 2,346,359 Claus Apr. 1l, 1944 2,490,100 Byrnes May 14, 1946 FOREIGN PATENTS Number Country Date 9,798 Great Britain 1895 4,157 Great Britain 1896 10,607 Great Britain 1903 164,379 Germany 1905 

